Chair seat



FIG. 1 is a perspective view of the chair seat according to my design, the broken lines of the portable, folding chair frame with a backrest are for illustrative purposes only and form no part of the claimed design;

FIG. 2 is a front view of the chair seat of FIG. 1;

FIG. 3 is a rear view of the chair seat of FIG. 1;

FIG. 4 is a bottom view of the chair seat of FIG. 1;

FIG. 5 is a left side view of the chair seat of FIG. 1, the right side being a mirror image thereof; and,

FIG. 6 is a top view of the chair seat of FIG. 1. 

I claim the ornamental design for a chair seat, as shown and described. 